Semipermeable liquid crystal display device and manufacturing method thereof

ABSTRACT

Simplified manufacturing method for active matrix type semipermeable liquid crystal display devices also having improved productivity. In a manufacturing method for an active matrix type semipermeable liquid crystal display device, an interlayered insulator film is formed and processed in process A for forming an interlayered insulator film on a silicon layer forming the source and drain of the TFT; in a process B for forming a photoresist layer on the interlayered insulator film; in a process C for forming the photoresist layer in a designated pattern using a mask formed with a pattern below the resolution limit in the section for forming the reflecting electrode; in a process D for patterning the photoresist layer made in process C as the etching mask for etching the interlayered insulator film. After the process D, a source electrode, signal lines, drain electrode and reflecting electrode are simultaneously formed from the metallic film.

RELATED APPLICATION DATA

The present application claims priority to Japanese Application No.P2000-361069, filed Nov. 28, 2000 and P2000-281023 filed Sep. 14, 2000,and is a divisional of U.S. application Ser. No. 09/951,066 filed Sep.12, 2001, all of which are incorporated herein by reference to theextent permitted by law.

FIELD OF THE INVENTION

The present invention relates to technology for shortening themanufacturing process for semipermeable liquid crystal display devicesby forming surface irregularities on the reflective electrodesimultaneously with forming openings on the permeable section of thepixel in the interlayered insulating film on silicon film formed withthe source and drain of the thin film transistor.

DESCRIPTION OF THE RELATED ART

The drive side of the TFT (thin film transistor) substrate of the activematrix type semipermeable liquid crystal display device of the relatedart having a reflective electrode composed of a reflective diffusionplate formed with surface irregularities, and also having a transparentelectrode made from transparent conductive film in the transparentsection of the pixel is fabricated as shown in FIG. 12A through FIG.12I. The process for fabricating liquid crystal devices having a pixelstructured from a bottom gate type TFT is shown in FIG. 12A through FIG.12I, however a pixel with a top gate type structure TFT is fabricated inbasically the same process.

As shown in 12A, a metallic film is first formed on a transparentsubstrate 1, and a gate G and an auxiliary capacitor electrode Cs formedby etching using photolithography, a gate insulation film 2 deposited,and a polysilicon film 3 formed.

Next, to prevent doping of impurities into the channels during impuritydoping of the source and drain regions, a stopper 4 is formed toself-align with the gate G on the polysilicon film comprising thechannels, and the source region and drain region are doped withimpurities.

Islands shapes are then formed separately on the polysilicon film 3using the photoresist process and the etching process, and a lowtemperature thin film transistor (TFT) is formed.

The interlayered insulator film 5 is formed next in FIG. 12B. Next, inorder to form contact holes and an opening for the pixel transparentsection, a photoresist layer 6 is first of all formed on theinterlayered insulator film 5, and the photoresist layer 6 is patternedin FIG. 12C by the photolithographic method using as a pattern mask, toform contact holes and an opening for the pixel permeable section T asthe photomask. Etching is then performed using the interlayeredinsulator film 5 as the etching mask, and contact holes H₁ and the pixelpermeable section T opening are formed (FIG. 12D).

The metallic film is then formed using a stopper etc. A signal line andsource electrode S₁ connecting to the TFT source S by way of the contacthole H₁ are formed by etching, and a drain source electrode D₁connecting to the drain D of the TFT by way of the contact hole H₁ isformed by etching as in FIG. 12E.

The irregularities forming the base of the surface irregularities of thereflecting electrode having a reflective diffuser function are formed asdescribed next using two layers of photoresist material. A first layer 7forming the basic structure of the irregular shape is formed byphotolithography using the photoresist material in FIG. 12F. Thephotomask is used to make openings for a second collector hole 2 andpixel permeable section T for conduction between the source electrode S₁and drain electrode D₁. Next, a second layer 8 for improving thereflection is formed as shown in FIG. 12G by photolithography using aphotoresist material identical to the first layer 7. The mask isutilized to make openings for the third collector hole H3 and pixelpermeable section T for connection with the drain electrode D₁. Asurface irregularity (rough) section is in this way formed from thefirst layer 7 and second layer 8 structure.

A transparent conducting film 9 constituting the transparent electrodeof the pixel permeable section T is next formed by sputtering, etc. Thistransparent conducting film 9 connects to the drain electrode D1 andcontact hole H3 as shown in FIG. 12H. The transparent conducting film 9also forms the reflecting section of the pixel and may also be used asthe base material (or underlayer) of the reflecting electrode.

A metallic film such as aluminum or silver having high reflectivity isnext deposited on the reflecting section R of the pixel, and areflecting electrode 10 is formed as in FIG. 12I by photolithography.

The drive side of the TFT substrate is in this way completed. Apolarizing film is coated on this TFT substrate, and opposing substrateformed of the color filter and opposing transparent electrode, and apolarizing process is performed, both the substrates are overlapped oneach other using a gap material to maintain a suitable gap between thesubstrates, liquid crystal injected and sealed to obtain the liquidcrystal display panel.

In the fabrication process for the drive side substrate of the TFT (thinfilm transistor) substrate of the active matrix type semipermeableliquid crystal display device of the related art as shown in FIG. 12Athrough FIG. 12I, a seventh and an eighth layer are formed fromphotoresist material to apply specified surface irregularities (roughshape) to a reflecting electrode 10, and since ultimately a total ofthree insulating layers including an interlayered insulator film 5 areformed between the reflecting electrode 10 and the silicon film formingthe source S and drain D of the TFT, that require patterning processesby respective lithographic methods, and further since a source electrodeS₁, a drain source electrode D₁, and a reflecting electrode 10 must beformed by separate processes, the problem occurs that many man-hours arerequired and the manufacturing cost is high.

SUMMARY OF THE INVENTION

Whereupon, the present invention has the object of providing a simpleand manufacturing process for an active matrix type semipermeable liquidcrystal display device yielding improved productivity.

To achieve the above objects, in the manufacturing process for thesemipermeable liquid crystal display device by the inventors of thepresent invention, a photoresist layer is formed on the interlayeredinsulator film on the silicon layer forming the source and drain of theTFT device, and corresponding surface irregularities are simultaneouslyformed on the reflecting electrode of the pixel reflecting section, andopening for the pixel transparent section on the photoresist layer, bypatterning with photolithographic methods utilizing a designatedphotomask on that photoresist layer, so that by forming surfaceirregularities (rough shapes) on the pixel reflecting sectionsimultaneous with forming an opening on the transparent section of thepixel in the interlayered insulator film, a greatly shortenedmanufacturing process for liquid crystal devices can in this way beobtained.

The present invention in other words, provides a manufacturing methodfor an active matrix type semipermeable liquid crystal display deviceconsisting of an interlayered insulator film on the silicon layerforming the source and drain of the TFT, a reflecting electrode formedwith surface irregularities (rough sections) on the interlayeredinsulator film in the pixel reflecting section, and a transparentelectrode consisting of a transparent conductive film on the pixeltransparent section, wherein in the forming and processing of theinterlayered insulator film in the following processes A through D;

A: is a process for forming an interlayered insulator film on a siliconlayer forming the source and drain of the TFT;

B: is a process for forming a photoresist layer on the interlayeredinsulator film;

C: a process for patterning the photoresist layer by thephotolithographic method wherein, in a process using a mask formed witha pattern below the resolution limit in the section forming thereflecting electrode, the photoresist layer is utilized as thephotomask, so that the photoresist layer corresponding to transparentsection of the pixel and the section forming the contact holes in theinterlayered insulator film of the drain and source can be completelyremoved, and so that surface irregularities can be formed in thephotoresist layer corresponding to the section forming the reflectingelectrode,D: a process using the photoresist layer patterned in process C as theetching mask for completely etching an opening in the interlayeredinsulator film for the transparent (permeable) section of the pixel andthe section for forming the contact holes, and for etching theinterlayered insulator film so that surface irregularities are formed inthe interlayered insulator film of the section forming the reflectingelectrode.

The invention further provides a manufacturing method in particularcomprising the following sequential processes performed after the Dprocess wherein,

E is a process for simultaneously forming from a metallic film; signalwiring and a source electrode connecting with the source by way ofcontact holes, and a reflecting electrode and drain electrode connectingto the drain by way of contact holes and signal wiring,F is a process for patterning a protective film in a region containingthe pixel transparent section and reflecting section, so that thesection forming the contact hole on the drain electrode as well as thesection for the transparent section of the pixel have openings,G is a process for forming a transparent conductive film so as tocomprise a pattern containing the pixel transparent section andreflecting section, and connect the transparent electrode and reflectingelectrode by way of the contact holes, and further in the F process, apatterning method is provided for forming a protective film from thephotoresist layer, characterized in that patterning is by thelithographic method, and in a process using a mask formed with a patternbelow the resolution limit in the section for forming the reflectingelectrode, the protective film is utilized as photomask, so that aprotective film corresponding to the section forming the drain electrodeand permeable sections of the pixel can be completely removed, andsurface irregularities (rough sections) can be formed in the protectivefilm corresponding to the section forming the reflecting electrode.

The invention further provides a manufacturing method comprising thefollowing sequential methods performed after the D process wherein,

E is a process for simultaneously forming from a metallic film; signalwiring and a source electrode connecting with the source by way ofcontact holes, and a reflecting electrode and drain electrode connectingto the drain by way of contact holes and signal wiring,G_(y) is a process for forming a transparent conductive film so as tocomprise a pattern containing the pixel transparent section andreflecting section, and connecting the transparent electrode andreflecting electrode,

The invention further provides a manufacturing method comprising thefollowing sequential methods performed after the D process wherein,

E_(x) is a process for simultaneously forming a pattern of transparentconductive film wherein said pattern contains signal wiring and a sourceelectrode connecting with the source by way of contact holes, and apermeable and reflecting section of a pixel, and a drain electrodeconnecting to the drain by way of contact holes,G_(x) is a process for forming a reflecting electrode from a filmcomposed of metallic film, and connecting to the reflecting electrodeand transparent electrode.

The present invention further provides an active matrix typesemipermeable liquid crystal display device consisting of an insulationlayer on a silicon film formed as the source and drain of the TFT, areflecting electrode formed with surface irregularities on the insulatorlayer in the reflecting section of the pixel, and a transparentelectrode film made from transparent conductive film in the transparentsection of the pixel wherein, the insulator layer is formed from onelayer of insulator film.

In a liquid crystal device in particular wherein, the transparentconducting film of the pixel transparent section is extended onto thereflecting electrode, the transparent conducting film connects with thereflecting electrode, and further, a protective film is formed betweenthe reflecting electrode and transparent conducting film, and the cellgap of the liquid crystal display cell is set at ½λ in the permeablesection and ¼λ in the reflecting section, and surface irregularities areformed in the transparent conducting film on the reflecting electrode inthis state.

A liquid crystal device of the present invention is provided wherein thetransparent conducting film and reflecting electrode are sequentiallylaminated on the reflecting section of the pixel, and the reflectingelectrode and transparent conductive film are connected.

In the manufacturing method for the active matrix type semipermeableliquid crystal display device of the present invention, a photoresistlayer is formed on the interlayered insulator film on the silicon filmof which the source and drain of the TFT are formed, and by patterningthat photoresist layer by utilizing a designated photomask, an openingwith a shape corresponding to the transparent section on the pixel andsurface irregularities corresponding to the reflecting electrode on thereflecting section of the pixel are formed on the photoresist layer, andby next etching the interlayered insulator film using the photoresistlayer as an etching mask, surface irregularities (rough shapes) can beformed on the reflecting electrode of the reflecting section of thepixel and an opening formed in the permeable section of the pixel on theinterlayered insulator film. The laminating processes for thephotoresist layer required in forming the surface irregularities on thereflecting electrode in the active matrix type semipermeable liquidcrystal display device of the related art can therefore be reduced, andthe source electrode, signal wiring, drain electrode and reflectingelectrode formed by separate processes in the related art can besimultaneously formed by forming one metallic film so that themanufacturing process for a liquid crystal device can be greatlysimplified, and productivity can be boosted.

Also in the present invention, the transparent conductive film isextended to the reflecting electrode, and the transparent conductivefilm and reflecting electrode are electrically connected, so the silverforming the reflecting electrode in the liquid crystal display cell istransferred to the opposing substrate and the crystallization phenomenoncan therefore be prevented.

Further in the present invention, by forming a protective film betweenthe reflecting electrode and the transparent conducting film, and byadjusting the thickness of that protective film, the opticalcharacteristics of the reflecting section and permeable section of thepixel can easily be optimized.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A through FIG. 1G are drawings showing the processes in themanufacturing method for the liquid crystal display device of thepresent invention.

FIG. 2A and FIG. 2B are drawings showing the processes in themanufacturing method for the liquid crystal display device of thepresent invention.

FIG. 3 is a cross sectional drawing of the thin film transistorsubstrate obtained by the manufacturing method of the present invention.

FIG. 4 is a cross sectional drawing of the thin film transistorsubstrate obtained by the manufacturing method of the present invention.

FIG. 5 is a flat view of a photomask having a line and space pattern.

FIG. 6 is a graph showing the interrelation of the photomask line andspaces, the exposure time, and reduction in film thickness of thephotoresist layer in the photolithographic process of the photoresistlayer.

FIG. 7 is a flat view of a photomask having a dot pattern.

FIG. 8 is a flat view of the photomask used on the photoresist layer.

FIG. 9A is a flat view of the photomask pattern for forming surfaceirregularities on the photoresist layer.

FIG. 9B is a side view of the photoresist layer surface irregularitiesformed by using the mask of FIG. 9A.

FIG. 10A is a flat view of the photomask pattern for forming surfaceirregularities on the photoresist layer.

FIG. 10B is a side view of the photoresist layer surface irregularitiesformed by using the mask of FIG. 10A.

FIG. 11 is a graph showing the interrelation of the reflectivity and thelevel difference of the surface irregularities of the reflectingelectrode.

FIG. 12A through FIG. 12I are drawings showing the processes in themanufacturing method for the active matrix type semipermeable liquidcrystal display device of the related art.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The embodiments of the present invention are hereafter described indetail while referring to the accompanying drawings. In the drawings,sections with the same reference numerals are the same or equivalentstructural components.

FIG. 1 is process drawings of the embodiment of the present inventionfor manufacturing a liquid crystal display device having a bottom gateTFT pixel structure.

First of all in this method, metallic film such as of molybdenum,chromium, aluminum, tantalum, wolfram as shown in FIG. 1A, is formed onthe transparent substrate 1, and a gate G and auxiliary capacitorelectrode Cs formed by dry etching using a photolithographic technique,and a silicon nitride film or silicon oxide film formed as the gateinsulator film 2 by sputtering or carrier vapor (CVD) deposition, thesefilms are formed in laminations, and a polysilicon film 3 furtherformed. The method for forming this polysilicon film 3 is for example,to first form an amorphous semiconductor layer on the gate insulatorfilm 2, and next perform dehydrogenation at a high temperature forlowering the hydrogen concentration of the semiconductor layer, andcrystallizing by an excimer laser, converting the semiconductor layerinto a polysilicon film. The dehydrogenation process may be omitted ifthe concentration of hydrogen atoms is less than one percent. The gateinsulator film and amorphous semiconductor layer are preferably formedconsecutively to obtain stable film quality.

A stopper 4 is next formed to self-align with the gate G on thepolysilicon film 3 forming the channel section to prevent injectionduring doping of impurities into the source region and drain region. Thestopper 4 here, is a stopper film formed from silicon oxide on the gateinsulator film 4, and then coated on top with resist, and by exposingthe rear side of the resist layer to light using the gate G as a mask,the resist is patterned so that the gate G self-aligns with the sectionformed as the channel, and etching of the stopper film further performedusing this resist layer as the mask, and so a stopper film remains inthe channel forming section.

The source and drain region are then doped with impurities using ionimplantation and ion doping techniques, and the source S and drain D areformed. The photoresist process and etching process are used to form thepolysilicon film into separate island shapes, and the TFT is formed. Theabove method for forming the TFT was a low-temperature polysiliconthin-film-transistor forming method, however the manufacturing method ofthe present invention may also be applied to forming amorphous siliconthin-film transistors.

The forming and processing of the interlayered insulator film is nextperformed using the processes A through D.

An interlayered insulator film 5 is formed (FIG. 1B) from inorganicinsulator material such as laminations of silicon nitride film andsilicon oxide film by the carrier vapor deposition (CVD) method orsputtering method.

In process B, a photoresist layer 6 is formed on the interlayeredinsulator film 5.

In process C, the photoresist layer 6 is patterned (FIG. 1C) by aphotolithographic technique. In this case, the photoresist layer 6 canbe completely removed from portions corresponding to the section forforming contact holes H₁ and the permeable section T of the pixel formedon the interlayered insulator film 5 of the source S and drain D; and apattern below the resolution limit of the stepper in the reflectingelectrode forming section can be formed using the photomask ofphotoresist layer 6 so that irregular surfaces are formed in thephotoresist layer 6 corresponding to the electrode forming section.

The actual photomask configuration can be experimentally determined byfinding the interrelation between the photomask pattern, and theexposure time and film thickness reduction of the photoresist layer. Forexample, when the line and space (hereafter abbreviated to L/S) patternshown in FIG. 5 is exposed to light with the stepper, the interrelationof the light exposure time and film thickness reduction amount of thephotoresist layer is changed according to the L/S (lines and spaces) asshown in FIG. 6. The “Window” outside the graph frame in FIG. 6 showsthe case when the S (space) resolution is greater than the lightexposure device. The numerals such as on the right side of the ×indicate the L (μm)/S (μm). In FIG. 6, when the section on thephotoresist layer for forming the contact hole is completely opened to alight exposure amount of 1200 milliseconds, it can be seen that thephotoresist layer can have a film thickness reduction amount of 0.6 μmwhen L=0.25 μm, S=0.50 μm is selected.

When experimentally finding the reduction in film thickness in this way,the dot pattern shown in FIG. 6 may also be utilized instead of the L/Spattern of FIG. 5.

Besides the above, a more detailed photomask configuration can becalculated from the optical index constant, and the photoresist layerfilm thickness can be controlled by the effective transmittance(permeance) rate of the photomask.

The actual photomask pattern is formed consecutively or in steps inpatterns not capable of being resolved by the stepper. When forming thesection 21 to completely open the photoresist layer to light exposureand forming the section for forming surface irregularities on thephotoresist layer, as shown in the photomask 20 of FIG. 8 for example,the pattern sections 22 forming the irregular section, can constitutethe plurality of fine, concentric, ring-shaped patterns 22 a shown inFIG. 9A not capable of being resolved by the stepper. By exposing anddeveloping the photoresist layer to light using this kind of photomask,not only can completely open sections and sections formed with surfaceirregularities be formed on the photoresist layer, but by heating andreflowing after developing as shown in FIG. 9B, each of the patternsforming the surface irregularities on the photoresist layer 6 can bemade into smooth shapes.

Particular patterns that correspond to the shapes of particular surfaceirregularities may be utilized as photomask patterns, such as thesurface irregularities formed on the interlayered insulator film 5 forenhancing the reflectivity of the reflecting electrode in a specificdirection. The plurality of ring patterns are for example madeoff-center (eccentric) as shown in FIG. 10A. By then using thisphotomask to expose and develop the photoresist layer 6, and by thenreflowing as necessary, each of the pattern shapes forming the surfaceirregularities of the photoresist layer 6, can be given a sharp inclineon one side, and can be given gentle incline on the other side surfaceas shown in FIG. 10B.

The reflectivity (rate) of the reflecting electrode is dependent on thelevel difference (step) formed in the photoresist layer 6 as shown inFIG. 11. The level difference of the pattern is determined by factorssuch as the pattern shape of the photomask and amount of exposure sothat the amount of light exposure on the photoresist layer 6 and thephotomask pattern can be set as needed by forming the level difference(step) to obtain the specified reflectivity for the reflectingelectrode.

When the interlayered insulator film 5 is dry-etched using the patternedphotoresist layer 6 as the etching mask, the shape of the photoresistlayer 6 is transferred to the interlayered insulator film 5. At thispoint, in the present invention, the process D is next performed.

In process D, the photoresist layer patterned in the above describedprocess C is used as the etching mask, and the interlayered insulatorfilm 5 etched by dry etching after removal of the resist layer by amethod such as the RIE method or the ICP method, so that the sectionforming the contact hole H₁ and the interlayered insulator film for thepermeable section of the pixel are completely opened, and surfaceirregularities are formed on the interlayered insulator film 5 at thesection for forming the reflecting electrode.

After the interlayered insulator film 5 is formed in the process D inthis way, any further laminating of insulator films is unnecessary forforming the surface irregularities on the reflecting electrode.Therefore, when limited to the forming a metallic film on thisinterlayered insulator film 5 to form a reflecting electrode, and on theother hand forming a transparent electrode made from a transparentconductive film in the transparent section of the pixel, a drive sideTFT substrate can easily be obtained and an active matrix typesemipermeable liquid crystal display device can be manufactured. In thiscase, the reflecting electrode and transparent electrode can be formedby the desired forming method and forming sequence, and an optionallayer such as a protective film can be added as needed. Further, liquidcrystal display panels can be fabricated by the normal method utilizingthis TFT substrate and liquid crystal display panels can bemanufactured.

The liquid crystal device manufactured in this way is the same as theactive matrix type semipermeable liquid crystal display device of theknown art in the points of having an insulator layer on a silicon filmcomprising the source S and drain D of the TFT, and having a reflectingelectrode made from reflective diffusion plate formed with surfaceirregularities, and also in having a transparent electrode made fromtransparent conductive film in the transparent section of the pixel.However this liquid crystal device is characterized in that theinsulator layer between the silicon film and the reflecting electrode isformed from one layer of insulator film. The present invention thereforealso includes the structure relating to the liquid crystal displaydevice.

The manufacturing method for the liquid crystal display device of thepresent invention including the processes subsequent to process D, isperformed sequentially in the following processes E through G as shownin FIG. 1E through FIG. 1G.

In process E, a high reflectivity metal such as aluminum, silver,aluminum alloy or silver alloy is deposited by sputtering to form themetallic film 11, and then a signal line and source electrode S₁connecting to the source S by way of the contact hole H₁, as well as areflecting electrode 10 and drain electrode D₁ connecting with the drainD by way of the contact hole H₁ are simultaneously formed by patterningby photolithographic methods and by etching in FIG. 1E. In this case,the structure of the metallic film 11 may comprise many layers of highreflectivity conductive film such as aluminum, silver, aluminum alloy orsilver alloy, and metallic film such as chromium, molybdenum, titanium,tantalum and wolfram.

In process F, a protective film 12 composed of photoresist is formed inthe region including the reflecting and permeable sections of the pixel.This protective film 12 is patterned so that the section formed with thedrain electrode D₁ and the permeable section T of the pixel haveopenings as in FIG. 1F. Silicon oxides for example, may be used in theforming methods to form the protective film 12 and patterning performedby photolithograpic and etching processes, however from the point ofview of shortening the process, preferably a film of photoresist isformed as in this process F, and patterning of that photoresist thenperformed only by a photolithographic process.

The thickness of the protective film 12 is preferably set so the cellgap of the liquid crystal display cell is ½λ in the permeable sectionand ¼λ in the reflecting section of the pixel. The cell gap for thiskind of liquid crystal display cell must generally meet specificationsthat demand brightness on the screen, however in the present invention,a cell gap can easily be formed by adjusting the thickness of theprotective film 12.

In process G, the transparent conductive film 9 is formed to be thepattern containing the reflecting section and permeable section of thepixel, and the TFT substrate obtained as shown in FIG. 1G. Thistransparent conductive film 9 is for example formed using ITO as asputtering method, and patterning then performed by a photolithographyprocess and an etching process. The transparent conductive film 9pattern may be formed only in the permeable sections of the pixel and inthe contact sections with the reflecting and permeable sections of thepixel however, rather than just the contact sections with the pixelreflecting and permeable sections, the transparent conductive film 9 canbe extended to the reflective electrode 10 and connected to the (same)electrical potential as the reflecting electrode 10 by way of thecontact hole H₂ so that the silver forming the reflecting electrode 10is transferred to the opposing substrate and the crystallizationphenomenon can be prevented in the liquid crystal cell.

The TFT substrate that was obtained, and the opposing (facing) substrateon which are formed the color filter and opposing transparent electrodeare coated with wiring polarizing film, and polarizing is performed,both substrates attached onto each other with sealer using the gapmaterial to maintain a suitable gap between the two substrates, and theliquid crystal is then injected and sealed to obtain the liquid crystaldisplay panel.

In another manufacturing method of the present invention, the sectionfor forming the contact hole H₂ on the drain electrode D₁ and thepermeable section T of the protective film 12 made of photoresist can becompletely removed in the patterning of the protective film 12 in theabove described process F, and a pattern below the resolution limit ofthe stepper in the reflecting electrode forming section formed using thephotomask of the protective film 12 so that irregular surfaces areformed in the reflecting electrode 10 forming section, and theprotective film 12 may be exposed and developed using the mask of thispattern. A protective film 12 such as in FIG. 2A can in this way bepatterned.

After the patterning of the protective film 12, the transparentconductive film 9 is formed to be the pattern containing the reflectingsection and permeable section of the pixel in process G described above,and the TFT substrate obtained. On the TFT substrate formed in this way,external light irradiating onto the section in the vicinity of the flatreflecting bottom of the surface irregularities of the reflectingelectrode 10 is scattered (or diffused), and the percentage of externallight irradiating onto the flat surface of the reflecting electrode 10is reduced, and also the light reflecting from the reflecting electrode10 is further scattered (or diffused) due to a differential in therefraction rate between the protective film 12 and the transparentconductive film 9, so that the reflecting properties of the reflectingsection R of the pixel can be improved.

In yet another manufacturing method of the present invention, afterforming the source electrode S₁, signal wiring, drain electrode D₁ andthe reflecting electrode 10, in the previously described process E,rather than forming the protective film 12 into a pixel region, thetransparent conductive film 9 may be formed in the same way as process G(process G_(y)) and a TFT substrate manufactured as shown in FIG. 3.

Also, after etching the interlayered insulator film 5, in a processE_(x), a pattern may be simultaneously formed of transparent conductivefilm 9 wherein said pattern contains signal wiring and a sourceelectrode S₁ connecting with the source S by way of contact holes H₁,and a permeable and reflecting section of a pixel, and a drain electrodeD₁ connecting to the drain D by way of contact holes H₁, and in aprocess G_(x), a reflecting electrode 10 may be formed, and thereflecting electrode 10 and transparent conductive film 9 are connectedby a film composed of aluminum, silver, aluminum alloy or silver alloy,and these processes are performed in sequence, and a TFT substrate maybe manufactured of laminations of the reflecting electrode 10 on thetransparent conductive film 9 as shown in FIG. 4. Here, when thetransparent conductive film 9 is formed by ITO, a film of molybdenum ortitanium is preferably formed beforehand on the ITO film, and themetallic film 11 then deposited afterwards.

The present invention was described while referring to the above workdrawings however, the present invention may constitute variousembodiments and configurations. For example, a liquid crystal displaydevice having a bottom gate TFT in the pixel structure was shown in thedrawings, however the present invention is also adaptable in the sameway to liquid crystal display devices having a top gate TFT in the pixelstructure.

1. A method of manufacturing an active matrix type semipermeable liquidcrystal display device comprising: an interlayered insulator film formedon a silicon layer, which is formed on a source and a drain of athin-film-transistor, which is located in a reflecting section of apixel; a reflecting electrode formed with surface irregularities on saidinterlayered insulator film in said reflecting section of said pixel;and a transparent electrode made of transparent conductive film formedin a transparent section of said pixel, the method comprising the stepsof: providing said silicon layer; and forming said interlayeredinsulating film by: forming an interlayered insulating film layer onsaid silicon layer; forming a photoresist layer on said interlayeredinsulator film layer; forming a photoresist mask having a pattern onsaid photoresist layer, the pattern formed in a section for forming thereflecting electrode, the pattern defining contact holes in thephotoresist layer corresponding to contact holes in the interlayeredinsulator film layer above the drain and source and surfaceirregularities in the photoresist layer; forming the contact holes andthe surface irregularities in the photoresist layer by dry etching usingthe photoresist mask as a mask; using the photoresist layer as a mask,forming an opening in the interlayered insulator film layer in thetransparent section of the pixel, the contact holes in the interlayeredinsulator film layer, and surface irregularities in a section of theinterlayered insulator film layer at which the reflecting electrode isformed by dry etching, such that the shape of the surface irregularitiesin the photoresist layer are transferred to the shape of the surfaceirregularities in the interlayered insulator film layer; and wherein thepattern formed in the section for forming the reflecting electrodecomprises a plurality of fine, ring-shaped patterns.
 2. A manufacturingmethod for a liquid crystal display device according to claim 1, whereinsaid photoresist layer is made of reflow.
 3. A manufacturing method fora liquid crystal display device according to claim 1, wherein theinterlayered insulator film heightens the reflectivity of saidreflecting electrode in a designated direction.
 4. A manufacturingmethod for a liquid crystal display device according to claim 1,comprising the following sequential processes performed after said Dprocess, wherein E: is a process for simultaneously forming from ametallic film; signal wiring and a source electrode connecting with saidsource by way of said contact holes, and a reflecting electrode anddrain electrode connecting to said drain by way of said contact holes,F: is a process for patterning a protective film in a region containingsaid pixel transparent section and reflecting section, so that thesection formed with said contact hole on said drain electrode as well asthe section for the transparent section of said pixel have openings, G:is a process for forming a transparent conductive film to comprise apattern containing said pixel transparent section and reflectingsection, and connect said transparent electrode and reflecting electrodeby way of said contact holes.
 5. A manufacturing method for a liquidcrystal display device according to claim 4, wherein in process F, aprotective film is formed from said photoresist, and in the patterningof said protective film, said protective film corresponding to thetransparent section of said pixel and the section for forming saidcontact hole on said drain electrode can be completely removed, and saidphotomask protective film used so that surface irregularities can beformed in said protective film corresponding to the section formed withsaid reflecting electrode, and patterning is performed by saidlithographic method, in a process using a mask forming a pattern belowthe resolution limit in the section forming said reflecting electrode,utilizing said protective film photomask.
 6. A manufacturing method fora liquid crystal display device according to claim 4 or claim 5, whereinthe film thickness of said protective film is adjusted so said cell gapof said liquid crystal display cell is ½λ in the permeable section and¼λ in the reflecting section of said pixel.
 7. A manufacturing methodfor a liquid crystal display device according to claim 1 comprising thesteps performed after the step of using the photoresist layer as a maskof: simultaneously forming, from a metallic film, a signal wiring and asource electrode connecting with said source via the contact holerespective to the source, and a reflecting electrode and a drainelectrode connecting to said drain via the contact hole respective tothe drain; and forming a transparent conductive film in said transparentsection and said reflecting section of said pixel and connecting saidtransparent electrode and said reflecting electrode.
 8. A manufacturingmethod for a liquid crystal display device according to claim 1comprising the following sequential processes performed after said Dprocess, wherein E_(x): is a process for simultaneously forming apattern from said transparent conductive film wherein said patterncontains a signal wiring and a source electrode connecting with saidsource by way of contact holes, and a permeable and reflecting sectionof a pixel, and said drain electrode connecting to said drain by way ofsaid contact holes, G_(x): a process for forming a reflecting electrodefrom metallic film, connecting to said reflecting electrode andtransparent electrode.